The major goal of the present experiments is to identify developmental changes in the acquisition of typing skill. These changes are sought in typists' eye movements, which are used to encode the to-be-typed text, in typists' manual keypress responses, which are to be precisely timed to produce the desired spatial sequencing of keystrokes, and in the coordination of oculomotor and manual responses. Experiments 1 to 5 specify the spatial and temporal parameters of text processing in copy typing and time-locking of oculomotor and manual responses. Experiments 6 to 8 attempt to identify informational units which are encoded via a series of eye fixations and used by the manual motor system to plan a sequence of keypress responses. Experiments 9 and 10 will discriminate the informational unit of motor planning from the unit of response execution. Eye movements and manual interkeypress responses are measured in Experiments 1 to 9. Experiments 1 to 5 also use eye movement contingent display changes that permit the experimenter to determine the amount and the timing of visual information that is available during a fixation in typing. Experiment 10 uses a simple reaction (typing) task in which single words are typed: no eye movements are measured in this study. The results of these experiments should impose constraints on a viable model of skilled typing and identify developmental changes in the acquisition of typing skill. In addition, the experiments may have implications for models of eye-hand coordination in general. For example, if skill acquisition involved the increased coordination of cognitive and/or motoric processes and if timing is the primary parameter of response coordination, then increases in typing skill should lead to increases in the time-locking of oculomotor and manual responses. The results of the experiments may also have implications for clinically impaired patient populations who use typewriter keyboards to communicate. Keyboards are currently used by the deaf to communicate over phone lines (TTY telephones). Furthermore, patients with articulatory deficits may use typewriter keyboards as a substitute for auditory language.